Short stories are like overnight bags. Pack them too full and they explode in mid-trip, scattering underclothes across the sidewalk; pack too little and they produce a dry embrassing rattle.

Peter Carey is plainly of the overstuffed suitcase school of story writing.

A former advertising executive who has established a reputation as one of Australia's leading experimental writers, he seems to draw his inspiration in equal parts from the Donald Barthelme-New Yorker school of fiction and from mainstream science fiction, particularly British masters like Brian Aldiss and John Wyndham.

The barthelme influence produces some of the weakest pieces in his book -- less stories than magazine squibs told in fragments and images so portentous as to be incoherent. The science-fiction influence has produced some stories that, so far from being experimental, could easily have run in The Magazine of Fantasy and Science Fiction 10 or 20 years ago. I don't mind; I enjoyed those issues of F&SF, just as I enjoyed Carey's story "Exotic Pleasure," about a bird from outer space who stimulates the human pleasure center while singlehandedly wrecking the earth's ecology.

But the strongest stories are a felicitous combination of the two streams. "The Chance" is about love, ugliness and mutability in a future in which humans can trade one body for another. A lonely man falls in love with a warm and beautiful woamn, only to discover that she belongs to a radical sect that seeks to make revolution by renouncing beauty and health for a misshapen "people's body." Her explanation captures some of the crazed self-abnegating spirit that infected the death agonies of the New Left: When I walk down the street people smile at me easily," she complains. "If I want help it comes easily. It is possible for me to do things like borrow money from strangers. I feel loved and protected. This is the privilege of my body which I must renounce."

New Left themes also echo in "War Crimes," in which a pair of rock'n'roll businessmen take over a declining frozen-food factory in the midst of an apocalyptic depression and revive it by providing the sales manager with heroin; he tightens financial procedures by beheading an embezzler. When his secretary displeases him, he shoots her in the foot with a .22 pistol, and then reflects, with the solemnity of an est graduate, "The incident made me think about myself and what I wanted from life."

Carey is certainly no stylist. His dialogue is hackneyed and silly, and many of his incidents are mechanical. But he is capable of an occasional marvelous sentence, as when a character boasts, "I have made it last, if you understand me, made my few pleasures last. On one occasion I made love to a lady of my acquaintance for thirty-two hours, she was often asleep."

But I found "The Fat Man in History" less interesting for its literary merit than for its view of America. As a nation we fascinate, obsess and enrage Carey. Often he portrays us in fashionable cliches -- crass tourists in Bermudas, brutal soldiers in sunglasses. But here is also a picture of Americans as quite literally creatures from outer space, crazed miracle workers who have changed the world into a place the other natives can barely recognize.

"We were used to not understanding," one of his characters muses when real spacemen arrive. "It had become a habit with the Americans, who had left us with a technology we could neither control or understand." The future Carey sees is a world that the Americans have created and then abandoned, leaving Carey and his characters clutching cardboard suitcasess, in a landscape of entropy and decline.

In contrast to Carey, John McGahern sports stylish luggage; he is like a man traveling to a weekend in the country, carrying a case with a change of clothes, a worn shooting-stick and a few smoked-meat sandwiches.

"Getting Through" begins with an invocation to Chekov; McGahern, an Irish writer whose latest novel, "The Pornographer," was praised by critics in Britain and the United States, can bear the comparison he invites.

For one thing, he is a magnificent craftsman of the language. When new knowledge hits a young golfer, it is "as if all the irons were being suddenly all truly struck and were flowing from all directions to the heart of the green." A man and a woman, caught in awkward and sexually ambiguous dealings, end their evening together: "We grimaced and waved goodnight to one another like any special pair of monkeys." When two old friends meet after lonely years, "it was like walking in the broken world of ourselves."

The theme of these stories is death -- the final "getting through" -- and the scores of small losses that prepare us for it. This daily loss is embodied in James Sharkey, an Irish schoolteacher who appears in "All Sorts of Impossible Things" and again in "Faith, Hope and Charity."

As a young man, Sharkey had courted Cathleen O'Neill, and "they'd thought time would wait for them forever." But one morning Sharkey finds himself jilted and balding, and he vows never again, through all the lonely years ahead, to take off his hat in company. The parish priest invokes the power of the church, which demands a bare head at mass; but even the church cannot arque with death. "You may have noticed recently, Father," Sharkey explains, "a certain manifestation that my youth is ended. Namely that I'm almost bald. It had the effect of timor mortis . So I decided to cover it up." Sharkey becomes "the hatted man," a symbol of death to his village, like the black harp that, McGahern records, the Irish Post Office puts on telegrams announcing a bereavement.

Both of these story collections have flaws. "The Fat Man in History" suffers from sloppiness and haste. In one of Carey's stories, the earth is visited with a plague of dematerialization, in which people and building simply fade away to nothing. I felt the same sensation reading many of Carey's own stories -- the sense that the words were slipping from my memory even as I read them. As for "Getting Through," it suffers sometimes from too much care, too much structure and constraint. Some of McGahern's stories rattle. But most are rich and worth reading more than once. Like a worn fine leather case, "Getting Through will be in my closet for years.